A magnetic conducting plate assembly, a sound production device and an electronic device

Abstract

The application discloses a magnetic conducting plate assembly, a sound production device and electronic equipment, and relates to the technical field of acoustics. The application discloses a magnetic conducting plate assembly, which comprises a body part, a first plating layer arranged on the peripheral side surface of the body part, and a second plating layer arranged on the top surface of the body part. The first plating layer and the second plating layer are both soft magnetic metal plating layers composed of polycrystalline material. The average thickness of the first plating layer is 1.2-5 times the average thickness of the second plating layer. The magnetic conducting plate assembly aims to solve the technical problem of how to improve the magnetic line constraint capability and corrosion resistance of the magnetic conducting plate assembly while ensuring good magnetic conducting performance.

Description

Technical Field

[0001] This invention relates to the field of acoustics, and more particularly to a magnetic plate assembly, a sound-generating device, and an electronic device. Background Technology

[0002] When a loudspeaker is working, the voice coil cuts through magnetic field lines in a magnetic field. The density of these magnetic field lines directly affects the driving force of the voice coil. The greater the magnetic flux density, the stronger the driving force of the voice coil, and the higher the amplitude and sensitivity in the mid-frequency range. The washer, as an important component of the magnetic circuit structure, is usually placed on top of the magnet and is used to converge the magnetic field lines into the magnetic gap, forming a concentrated working magnetic field.

[0003] In conventional technologies, washers often employ a uniform thickness design, and due to space constraints imposed by the ultra-thin and lightweight requirements of consumer electronics, their overall thickness is typically quite thin. This results in limited constraint of magnetic lines of force within the washer, and a narrower uniform distribution of magnetic lines of force within the magnetic gap. Consequently, the effective space for stable vibration of the speaker is relatively small, hindering further improvement in acoustic performance. Furthermore, to meet corrosion resistance requirements, the surface of magnetically conductive components such as washers typically requires an anti-corrosion coating. However, conventional coatings generally employ a uniform thickness design; if the coating is too thin, the corrosion resistance is insufficient; if the coating is too thick, its magnetic permeability is lower than that of the soft magnetic substrate, leading to increased magnetic reluctance in the overall magnetic circuit, thereby weakening the speaker's driving force and frequency response characteristics. Therefore, how to improve the magnetic line constraint capability and corrosion resistance of the magnetically conductive plate assembly while ensuring good magnetic permeability has become a pressing technical problem to be solved in this field. Summary of the Invention

[0004] The main objective of this invention is to provide a magnetic conductive plate assembly, a sound-generating device, and an electronic device, aiming to solve the technical problem of how to improve the magnetic field line confinement capability and corrosion resistance of the magnetic conductive plate assembly while ensuring good magnetic conductivity.

[0005] To achieve the above objectives, embodiments of the present invention provide a magnetic conductive plate assembly, the magnetic conductive plate assembly comprising: a body portion, a first plating layer on the peripheral side surface of the body portion, and a second plating layer on the top surface of the body portion, wherein both the first plating layer and the second plating layer are soft magnetic metal plating layers composed of polycrystalline materials, and the average thickness of the first plating layer is 1.2 to 5 times the average thickness of the second plating layer.

[0006] In one embodiment, the average thickness of the first coating is 3 to 50 μm.

[0007] In one embodiment, the average thickness of the second coating is 1~20 μm.

[0008] In one embodiment, the average thickness of the first coating is less than or equal to 50% of the average thickness of the body portion.

[0009] In one embodiment, the bottom surface of the body portion is provided with a third coating, which is a soft magnetic alloy coating composed of polycrystalline materials, and the average thickness of the third coating is 0.05 to 1 times the average thickness of the second coating.

[0010] In one embodiment, the average thickness of the third coating is 1~10 μm.

[0011] In one embodiment, the surface tension of the third coating is 20~70 dyn / cm.

[0012] In one embodiment, the roughness of the third coating is 0.05~3 μm.

[0013] In one embodiment, the third coating contains at least two elements selected from iron, cobalt, and nickel.

[0014] In one embodiment, the saturation magnetic induction intensity of the third coating is 0.5~3 T.

[0015] In one embodiment, the third coating is primed, and the prime agent used in the primed treatment includes at least one of silane coupling agent, epoxy primer and acrylic primer.

[0016] In one embodiment, the third coating is prepared by at least one of electroplating, electroless plating, diffusion plating, and physical vapor deposition.

[0017] In one embodiment, the third coating is a single-layer or multi-layer structure.

[0018] In one embodiment, the second coating is subjected to a sealing treatment, wherein the sealing agent used in the sealing treatment includes at least one of an aqueous sealing agent, an oil-based sealing agent, and a nanocomposite sealing agent.

[0019] In one embodiment, the charge transfer resistance of the second coating in a 3.5 wt.% NaCl solution is 1~200 KΩ·cm. 2 .

[0020] In one embodiment, the first coating contains at least two elements selected from iron, cobalt, and nickel.

[0021] In one embodiment, the second coating contains nickel, and the mass percentage of nickel in the second coating is greater than 60%.

[0022] In one embodiment, the saturation magnetic induction intensity of the first coating is 0.5~3 T.

[0023] In one embodiment, the elastic modulus of the first coating is 100~300 GPa.

[0024] In one embodiment, the elastic modulus of the second coating is 100~300 GPa.

[0025] In one embodiment, the first coating is prepared by at least one of electroplating, electroless plating, diffusion plating, and physical vapor deposition.

[0026] In one embodiment, the second coating is prepared by at least one of electroplating, electroless plating, diffusion plating, and physical vapor deposition.

[0027] In one embodiment, the first coating is a single-layer or multi-layer structure.

[0028] In one embodiment, the second coating is a single-layer or multi-layer structure.

[0029] To achieve the above objectives, embodiments of the present invention provide a sound-generating device, the sound-generating device including a housing and a magnetic circuit structure disposed on the housing, the magnetic circuit structure including a magnet assembly and a magnetic guide plate assembly as described above, the magnetic guide plate assembly including at least one of a magnetic guide yoke and a magnetic guide plate disposed at one end of the magnet assembly away from the magnetic guide yoke.

[0030] To achieve the above objectives, embodiments of the present invention provide an electronic device, which includes the magnetic plate assembly described above, or the sound-generating device described above.

[0031] This invention provides a magnetic guide plate assembly, comprising: a body portion, a first coating on the peripheral side of the body portion, and a second coating on the top surface of the body portion. Both the first and second coatings are soft magnetic metal coatings composed of polycrystalline materials, and the average thickness of the first coating is 1.2 to 5 times the average thickness of the second coating. In this invention, the first and second coatings are both soft magnetic metal coatings composed of polycrystalline materials, possessing high permeability and saturation magnetic induction intensity, effectively constraining magnetic lines of force, and allowing the magnetic lines of force in the magnetic circuit structure to be conducted along a predetermined path. Since the magnetic lines of force mainly emanate from the side of the body portion, the side needs to bear a high magnetic flux density. Therefore, this invention sets the average thickness of the first coating to 1.2 to 5 times the average thickness of the second coating, meaning the first coating has a thicker magnetic guide metal structure, which effectively prevents local magnetic saturation on the side. Simultaneously, when the magnetic lines of force diverge at the edges, the thicker coating has a stronger magnetic line constraint capability, thereby optimizing the distribution of magnetic lines of force, increasing the magnetic flux density in the magnetic gap, and improving the driving force and frequency response characteristics of the speaker. Meanwhile, the second coating is located on the top surface of the main body. This region has a relatively low magnetic flux density and low requirements for magnetic permeability; its main function is corrosion protection. Therefore, the second coating can be made relatively thin, allowing the entire magnetic plate assembly to meet the functional requirements of different parts while avoiding unnecessary increases in materials and costs. Furthermore, by reasonably controlling the thickness difference between the first and second coatings, this embodiment of the invention ensures good stress distribution characteristics in the transition region, avoiding stress concentration and coating cracking caused by excessive thickness differences. It also avoids the defects of excessive internal stress, easy coating peeling, and increased manufacturing costs caused by an excessively thick first coating. This allows the magnetic plate assembly to maintain excellent magnetic permeability and corrosion resistance while also possessing good structural integrity. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the magnetic conductive plate assembly involved in the embodiment of the present invention; Figure 2 This is a schematic diagram of the sound-generating device involved in the embodiment of the present invention; Figure 3 This is a schematic diagram of the mid-frequency acoustic performance test results of the embodiment of the present invention.

[0033] Explanation of reference numerals in the attached figures 100. Magnetic plate assembly; 101. Main body; 102a, First coating; 102b, Second coating; 102c, Third coating; 101a, Central magnetic plate; 101b, Side magnetic plate; 101c, Magnetic yoke; 200. Sound-generating device; 201. Housing; 202. Magnetic gap; 203. Diaphragm assembly; 204. Voice coil; 205a, center magnet; 205b, side magnet.

[0034] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0036] Hereinafter, embodiments of the magnetic plate assembly, sound-generating device, and electronic device of the present invention are disclosed in detail with appropriate reference to the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present invention and are not intended to limit the subject matter of the claims.

[0037] The "range" disclosed in this invention is defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for specific parameters, it is understood that ranges of 60~110 and 80~120 are also expected. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this invention, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0038] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0039] Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0040] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments. However, the present invention is not limited to the listed embodiments, but should also include any other known modifications within the scope of the claims of the present invention.

[0041] To better understand the technical solution of the present invention, a detailed description will be provided below in conjunction with the accompanying drawings and specific embodiments.

[0042] This invention provides a magnetic guide plate assembly, with reference to... Figure 1 The magnetic plate assembly 100 includes: a body portion 101, a first plating layer 102a on the peripheral side of the body portion 101, and a second plating layer 102b on the top surface of the body portion 101. Both the first plating layer 102a and the second plating layer 102b are soft magnetic metal plating layers composed of polycrystalline materials. The average thickness of the first plating layer 102a is 1.2 to 5 times the average thickness of the second plating layer 102b.

[0043] Optionally, the magnetic plate assembly 100 can be applied to a sound-generating device, which includes a magnetic structure comprising the magnetic plate assembly 100 and a magnet assembly. The side of the body portion 101 furthest from the magnet assembly is the top surface of the body portion 101, and the side of the body portion 101 closest to the magnet assembly is the bottom surface of the body portion 101.

[0044] Optionally, at least one circumferential side of the body portion 101 is provided with a first plating layer 102a.

[0045] Optionally, the average thickness of the first coating 102a is 1.2 times, 1.5 times, 2 times, 2.5 times, 3 times, 3.5 times, 4 times, 4.5 times, 5 times, etc., the average thickness of the second coating 102b.

[0046] Optionally, the average thickness of the first coating 102a is 1.5 to 3 times the average thickness of the second coating 102b.

[0047] In this embodiment, the average thickness of the first coating 102a located on the peripheral side of the body portion 101 is greater than the average thickness of the second coating 102b located on the top surface of the body portion 101. This effectively prevents local magnetic saturation on the side. Furthermore, when magnetic lines of force diverge at the edges, the thicker coating provides stronger magnetic line constraint, thereby optimizing the distribution of magnetic lines of force, increasing the magnetic flux density in the magnetic gap, and improving the driving force and frequency response characteristics of the speaker. Meanwhile, the second coating 102b is located on the top surface of the body portion 101. This area has a relatively low magnetic flux density and does not require high magnetic conductivity; its main function is corrosion protection. Therefore, the second coating 102b can be made relatively thin, allowing the entire magnetic conductive plate assembly 100 to meet the functional requirements of different parts while avoiding unnecessary increases in materials and costs.

[0048] Optionally, the magnetic plate assembly 100 includes at least one of a magnetic yoke and a magnetic plate.

[0049] Optionally, the body part 101 is a basic structural component in the magnetic plate assembly 100 that plays a role in bearing and guiding magnetism, and it is itself a magnetic guiding component in the magnetic circuit structure.

[0050] It should be noted that the magnetic plate assembly 100 in this embodiment of the invention is a magnetically conductive component with the aforementioned coating on its surface, applied in the magnetic circuit structure of a sound-generating device (e.g., a loudspeaker). The magnetic plate assembly 100 can be understood as an integral component formed by the coating of this embodiment of the invention on the surfaces of the magnetic yoke (i.e., the frame) and / or the magnetic plate (i.e., the washer) in the magnetic circuit structure of the sound-generating device. That is, the magnetic plate assembly 100 can be an assembly composed of the magnetic yoke and its surface coating, or an assembly composed of the magnetic plate and its surface coating, or both. Therefore, the magnetic plate assembly 100 in this embodiment of the invention is not limited to a single component at a specific location, but generally refers to a magnetically conductive component with the aforementioned coating features of this invention on its surface. In this embodiment of the invention, the magnetic plate assembly 100 can function as a magnetic yoke, a magnetic plate, or both, depending on the specific design requirements.

[0051] In this embodiment, both the first coating 102a and the second coating 102b are soft magnetic metal coatings composed of polycrystalline materials, possessing high permeability and saturation magnetic induction intensity. These effectively constrain magnetic field lines, allowing them to conduct along a predetermined path within the magnetic circuit structure. Since the magnetic field lines mainly originate from the side of the main body 101, and the side needs to bear a high magnetic flux density, this embodiment sets the average thickness of the first coating 102a to 1.2 to 5 times the average thickness of the second coating 102b. This means the first coating 102a has a thicker magnetically conductive metal structure, effectively preventing localized magnetic saturation on the side. Furthermore, when the magnetic field lines diverge at the edges, the thicker coating provides stronger magnetic field line constraint, thereby optimizing the magnetic field line distribution, increasing the magnetic flux density in the magnetic gap, and improving the speaker's driving force and frequency response characteristics. Meanwhile, the second coating 102b is located on the top surface of the main body 101. This region has a relatively low magnetic flux density and low requirements for magnetic permeability; its main function is corrosion protection. Therefore, the second coating 102b can be made relatively thin, allowing the entire magnetic plate assembly 100 to meet the functional requirements of different parts while avoiding unnecessary increases in materials and costs. Furthermore, by reasonably controlling the thickness difference between the first coating 102a and the second coating 102b, this embodiment of the invention enables the coating to have good stress distribution characteristics in the transition region, avoiding stress concentration and coating cracking caused by excessive thickness differences. It also avoids the defects of excessive internal stress, easy coating peeling, and increased manufacturing costs caused by an excessively thick first coating 102a. This ensures that the magnetic plate assembly 100 maintains excellent magnetic permeability and corrosion resistance while also possessing good structural integrity.

[0052] In one feasible embodiment, the average thickness of the first coating 102a is 3 to 50 μm; for example, the average thickness of the first coating 102a is 3 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, etc.

[0053] In one feasible embodiment, the average thickness of the second coating 102b is 1~20 μm; for example, the average thickness of the second coating 102b is 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, etc.

[0054] In one alternative embodiment, the average thickness of the first plating layer 102a is less than or equal to 50% of the average thickness of the body portion 101. For example, the average thickness of the first plating layer 102a is less than or equal to 50%, 45%, 40%, 35%, 30%, 35%, 20%, etc., of the average thickness of the body portion 101.

[0055] In this embodiment, if the thickness of the first plating layer 102a is too thin, and the thickness difference between it and the second plating layer 102b is too small, the optimization effect of the first plating layer 102a on the magnetic plate assembly 100 will not be significant. If the first plating layer 102a is too thick, the internal stress will be large, the first plating layer 102a will be prone to peeling off, and the manufacturing cost will be higher. At the same time, if the thickness difference between the first plating layer 102a and the second plating layer 102b is too large, stress concentration will easily form at the transition between the first plating layer 102a and the second plating layer 102b, causing the plating layer to crack. In addition, the second plating layer 102b is located on the top surface of the body portion 101, where the magnetic flux is relatively reduced, and it mainly plays a role in corrosion prevention. Therefore, the second plating layer 102b does not need to be too thick; however, if the thickness of the second plating layer 102b is too thin, its corrosion prevention performance will be insufficient. Therefore, by setting the average thickness and thickness relationship between the first coating layer 102a and the second coating layer 102b, the magnetic plate assembly 100 can ensure excellent magnetic permeability and corrosion resistance while also having good structural integrity.

[0056] In one feasible implementation, refer to Figure 1 The bottom surface of the main body 101 is provided with a third plating layer 102c. The third plating layer 102c is a soft magnetic alloy plating layer composed of polycrystalline materials. The average thickness of the third plating layer 102c is 0.05 to 1 times the average thickness of the second plating layer 102b.

[0057] Alternatively, the bottom surface of the body 101 can be the side closest to the magnet assembly.

[0058] Optionally, the average thickness of the third coating 102c is 0.05 times, 0.1 times, 0.2 times, 0.3 times, 0.4 times, 0.5 times, 0.6 times, 0.7 times, 0.8 times, 0.9 times, or 1 times the average thickness of the second coating 102b.

[0059] In one feasible embodiment, the average thickness of the third coating 102c is 1~10 μm; for example, the average thickness of the third coating 102c is 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, etc.

[0060] In this embodiment, the third plating layer 102c is located on the side of the body portion 101 near the magnet assembly. It needs to be bonded to the magnet assembly. If the thickness of the third plating layer 102c, located between the magnet assembly and the body portion 101, is too thick, it will increase the magnetic field path, increase the magnetic gap, and be detrimental to magnetic conductivity. If the thickness of the third plating layer 102c is too thin, the adhesive may directly contact the body portion 101. Since the adhesive is generally acidic, it will corrode the body portion 101, thereby affecting the magnetic conductivity. Therefore, in this embodiment of the invention, the thickness of the third plating layer 102c needs to meet the above conditions.

[0061] In one feasible embodiment, the surface tension of the third coating 102c is 20~70 dyn / cm; for example, the surface tension of the third coating 102c is 20 dyn / cm, 30 dyn / cm, 40 dyn / cm, 50 dyn / cm, 60 dyn / cm, 70 dyn / cm, etc.

[0062] In this embodiment, the third coating layer 102c is the bonding surface between the magnetic plate assembly 100 and the magnet assembly. In order to improve its adhesion, the surface tension of the third coating layer 102c is determined to be 20~70 dyn / cm. The higher the surface tension of the third coating layer 102c (i.e., the higher the surface energy), the easier it is to be wetted by the adhesive and the better the adhesion. However, if the surface tension is too high, it will be too active and easily adsorb impurities such as water vapor in the air, which will affect the adhesion. Conversely, if the surface tension is too low, the adhesive will be difficult to spread on the surface of the third coating layer 102c and the adhesion will be poor.

[0063] In one feasible embodiment, the roughness of the third coating 102c is 0.05~3 μm; for example, the roughness of the third coating 102c is 0.05 μm, 0.1 μm, 0.2 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, etc.

[0064] In this embodiment, the third coating 102c is the bonding surface between the magnetic plate assembly 100 and the magnet assembly. In order to improve its bonding force, the roughness of the third coating 102c is determined to be 0.05~3 μm in this embodiment of the invention.

[0065] In one feasible embodiment, the third coating 102c contains at least two elements selected from iron, cobalt, and nickel.

[0066] In one feasible embodiment, the saturation magnetic induction intensity of the third coating 102c is 0.5~3 T; for example, the saturation magnetic induction intensity of the third coating 102c is 0.5 T, 1 T, 1.5 T, 2 T, 2.5 T, 3 T, etc.

[0067] In this embodiment, saturation magnetic induction intensity refers to the magnetic induction intensity inside the coating that increases as the external magnetic field strength increases, eventually reaching a saturation value. After saturation, no matter how much the external magnetic field strengthens, the magnetic induction intensity inside the material hardly increases anymore. Therefore, the greater the saturation magnetic induction intensity, the more magnetic lines of force can pass through, and the better the magnetic permeability. The third coating 102c contains at least two ferromagnetic elements, which have a synergistic effect produced by the combination of multiple elements. This can improve the chemical affinity and bonding strength between the surface of the third coating 102c and the adhesive, making the adhesion between the magnetic plate assembly 100 and the magnet more firm and reliable. At the same time, the coexistence of at least two ferromagnetic elements can also maintain or even enhance the local magnetic permeability at the bottom, avoiding an increase in magnetic resistance due to the coating, thereby achieving a balance between magnetic permeability and adhesion.

[0068] In one feasible embodiment, the third coating 102c is primed, and the prime agent used in the primed treatment includes at least one of silane coupling agent, epoxy primer and acrylic primer.

[0069] Optionally, the silane coupling agent has a bifunctional molecular structure YR-SiX3, where the X group is generally methoxy, ethoxy, etc., which reacts with water to generate reactive silanol groups. These silanol groups undergo condensation reactions with hydroxyl groups on the coating surface to form Si-OM chemical bonds, where M is a metal atom, thus firmly binding the coupling agent to the coating surface. The Y at the other end of the silane coupling agent is an amino epoxy group or other group that readily reacts with adhesives, thus further enhancing its adhesion.

[0070] Optionally, the epoxy primer is generally a two-component compound, wherein the epoxy resin matrix penetrates into the pits on the surface of the third coating 102c, and the epoxy resin surface contains a large number of polar groups, which can form strong hydrogen bonds with the oxides on the surface of the third coating 102c; the active groups in the adhesive react chemically with the hydroxyl groups and other groups in the epoxy primer to form strong covalent bonds, thereby improving the adhesion of the third coating 102c.

[0071] In this embodiment, the primer can change the surface energy of the third coating 102c and react with the adhesive to improve the adhesion. At the same time, the primer can also form a dense film, which can also improve the corrosion resistance of the third coating 102c to a certain extent.

[0072] In one feasible embodiment, the third coating 102c is prepared by at least one of electroplating, electroless plating, diffusion plating and physical vapor deposition.

[0073] In one feasible embodiment, the second coating 102b is prepared by at least one of electroplating, electroless plating, diffusion plating and physical vapor deposition.

[0074] In one feasible embodiment, the first coating 102a is prepared by at least one of electroplating, electroless plating, diffusion plating and physical vapor deposition.

[0075] In this embodiment, electroplating utilizes an applied current to deposit metal cations onto the cathode surface, forming a coating. This process is mature, low-cost, and has a fast deposition rate. Chemical plating, on the other hand, uses a chemical catalytic reaction to deposit metal ions onto the surface of a magnetic plate, resulting in a dense and uniform coating with good corrosion resistance. Physical vapor deposition offers advantages such as high coating purity and density, and allows for precise control of thickness and composition.

[0076] In one feasible embodiment, the third coating 102c has a single-layer or multi-layer structure. For example, the third coating 102c has 1 layer, 2 layers, 3 layers, n layers, etc.

[0077] In one feasible embodiment, the second coating 102b has a single-layer or multi-layer structure. For example, the second coating 102b has 1 layer, 2 layers, 3 layers, n layers, etc.

[0078] In one feasible embodiment, the first coating 102a has a single-layer or multi-layer structure. For example, the first coating 102a has 1 layer, 2 layers, 3 layers, n layers, etc.

[0079] In this embodiment, the preparation process of a single-layer coating is simple and low-cost, while the multi-layer structure can suppress crack propagation and significantly improve the corrosion resistance of the coating. Therefore, the coating structure can be set according to the actual situation.

[0080] In one feasible embodiment, the second coating 102b is subjected to a sealing treatment, and the sealing agent used in the sealing treatment includes at least one of an aqueous sealing agent, an oil-based sealing agent, and a nanocomposite sealing agent.

[0081] Optionally, the water-based sealing agent includes at least one of silicone-based sealing agents, polyurethane-based sealing agents, acrylate-based sealing agents, and epoxy resin-based sealing agents, which can form a transparent and dense organic polymer film on the surface of the second coating 102b to isolate air and moisture.

[0082] Optionally, the oily sealant includes at least one of mineral oil and synthetic oil, which utilizes the hydrophobicity of the oil to form an oil film on the surface of the second coating 102b, isolating air and moisture.

[0083] Optionally, the nanocomposite sealing agent includes a polymer containing nanoparticles such as nano-silica and nano-alumina, which relies on nanoparticles to fill the micropores on the coating surface, thereby improving the density and corrosion resistance of the second coating.

[0084] In this embodiment, the surface of the second coating 102b has microscopic pores, through which water, oxygen, chloride ions, etc., can directly reach the surface of the body 101, causing corrosion of the body 101. However, this embodiment of the invention, through a pore-sealing process, can fill these pores on the surface of the second coating 102b, cutting off the intrusion path of corrosive media and improving corrosion resistance.

[0085] In one feasible embodiment, the charge transfer resistance of the second coating 102b in a 3.5 wt.% NaCl solution is 1~200 KΩ·cm. 2 For example, 1 kΩ·cm 2 10 KΩ·cm 2 50 KΩ·cm 2 100 KΩ·cm 2 150 KΩ·cm 2 200 KΩ·cm 2 wait.

[0086] Optionally, charge transfer resistance reflects the ease of electrochemical reactions at the metal / electrolyte interface. A higher charge transfer resistance means greater resistance to charge transfer from the metal surface to the solution during corrosion, indicating better corrosion resistance of the material. If the charge transfer resistance of the second coating 102b is too low, it is prone to corrosion, failing to provide adequate protection for the body 101, leading to corrosion of the body 101 and a sharp decrease in magnetic permeability. Furthermore, theoretically, a higher charge transfer resistance is better, but excessively high resistance usually requires increasing the coating thickness or using more expensive materials. Therefore, in this embodiment of the invention, the charge transfer resistance of the second coating 102b in a 3.5 wt.% NaCl solution is set to 1~200 KΩ·cm. 2 Within this range, it can provide protection for the main body 101 without affecting its magnetic conductivity or excessively increasing costs.

[0087] Optionally, the charge transfer resistance can be measured using an electrochemical workstation, with a saturated calomel electrode as the reference electrode and a platinum electrode as the auxiliary electrode. The frequency scan range is 1 MHz to 0.1 Hz, the test equilibrium potential is the open circuit potential, and the perturbation amplitude is ±5 mV.

[0088] In one feasible embodiment, the second plating layer 102b contains nickel, and the mass percentage of nickel in the second plating layer 102b is greater than 60%. For example, the mass percentage of nickel in the second plating layer 102b is greater than 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, etc.

[0089] In this embodiment, by controlling the mass percentage of nickel in the second coating 102b to be above 60%, the second coating 102b possesses alloy characteristics dominated by nickel. Nickel itself has excellent resistance to atmospheric corrosion and salt spray corrosion. The high nickel content allows a dense and stable passivation film to form on the coating surface, effectively preventing corrosive media from penetrating into the substrate, thereby providing long-term reliable corrosion protection for the body 101. At the same time, when the nickel content exceeds 60%, the coating exhibits a face-centered cubic structure, possessing good plasticity and toughness, and can adapt to slight deformations during product manufacturing and handling without cracking or peeling.

[0090] In one feasible embodiment, the first coating 102a contains at least two elements selected from iron, cobalt, and nickel.

[0091] In this embodiment, iron, cobalt, and nickel are all ferromagnetic elements, but each has different magnetic properties. Iron has a high saturation magnetic induction, cobalt has a high Curie temperature and low magnetocrystalline anisotropy, and nickel has good corrosion resistance and ductility. When at least two elements coexist in the same coating, the first coating 102a can combine the advantages of each element. For example, the iron-cobalt combination can significantly improve the saturation magnetic flux density and permeability, the iron-nickel combination can achieve low coercivity and excellent soft magnetic properties, and the cobalt-nickel combination can improve corrosion resistance while maintaining good magnetism. The solid solution or grain boundary segregation of multiple elements can also refine the grains, enabling the first coating 102a to have a higher magnetic flux carrying capacity when undertaking the task of confining high magnetic flux density on the periphery, thereby more effectively optimizing the distribution of magnetic field lines and increasing the magnetic flux density in the magnetic gap.

[0092] In one feasible embodiment, the saturation magnetic induction intensity of the first coating 102a is 0.5~3 T; for example, the saturation magnetic induction intensity of the first coating 102a is 0.5 T, 1 T, 1.5 T, 2 T, 2.5 T, 3 T, etc.

[0093] Optionally, the saturation magnetic induction intensity of the first coating 102a is 0.8~2.5 T.

[0094] In this embodiment, saturation magnetic induction intensity refers to the magnetic induction intensity inside the coating that increases as the applied magnetic field strength increases, eventually reaching a saturation value. After saturation, no matter how much the external magnetic field strengthens, the magnetic induction intensity inside the material hardly increases anymore. Therefore, the greater the saturation magnetic induction intensity, the more magnetic lines of force can pass through, and the better the magnetic permeability. The first coating 102a contains at least two ferromagnetic elements, which have a synergistic effect produced by the combination of multiple elements. This can improve the chemical affinity and bonding strength between the surface of the first coating 102a and the adhesive, making the adhesion between the magnetic plate assembly 100 and the magnet more firm and reliable. At the same time, the coexistence of at least two ferromagnetic elements can also maintain or even enhance the local magnetic permeability of the bottom, avoiding an increase in magnetic resistance due to the coating, thereby achieving a balance between magnetic permeability and adhesion.

[0095] In one feasible embodiment, the elastic modulus of the first coating 102a is 100~300 GPa; for example, the elastic modulus of the first coating 102a is 100 GPa, 150 GPa, 200 GPa, 250 GPa, 300 GPa, etc.

[0096] In one feasible embodiment, the elastic modulus of the second coating 102b is 100~300 GPa; for example, the elastic modulus of the second coating 102b is 100 GPa, 150 GPa, 200 GPa, 250 GPa, 300 GPa, etc.

[0097] In this embodiment, by controlling the elastic modulus of the first coating 102a and the second coating 102b within the range of 100~300 GPa, the magnetic plate assembly 100 possesses balanced mechanical matching characteristics. If the elastic modulus of the first coating 102a and / or the second coating 102b is too high, due to the asymmetrical coating design of the upper surface and the peripheral side of the body 101, the large difference in modulus between the two coatings will lead to uneven distribution of overall internal stress, causing the body 101 to bend and deform, thereby affecting the subsequent assembly accuracy with the magnet assembly and the consistency of the magnetic gap. If the elastic modulus of the first coating 102a and / or the second coating 102b is too low, the first coating 102a and / or the second coating 102b will have insufficient resistance to external deformation, making them prone to damage or cracking during product manufacturing, turnover, and assembly, thereby weakening the constraint ability of the first coating 102a on the peripheral magnetic lines of force and the anti-corrosion protection effect of the second coating 102b on the top surface. In this embodiment of the invention, by controlling the elastic modulus of the first coating 102a and the second coating 102b within a reasonable range, the magnetic plate assembly 100 can avoid internal stress imbalance and bending deformation caused by excessively high modulus, and can also avoid mechanical weakness and functional failure of the coating caused by excessively low modulus.

[0098] This invention also provides a sound-generating device, which includes a housing and a magnetic circuit structure disposed on the housing. The magnetic circuit structure includes a magnet assembly and a magnetic guide plate assembly as described above. The magnetic guide plate assembly includes at least one of a magnetic guide yoke and a magnetic guide plate disposed at the end of the magnet assembly away from the magnetic guide yoke.

[0099] Optionally, refer to Figure 2 The sound-generating device 200 includes a housing 201 and a magnetic circuit structure disposed on the housing 201. The magnetic circuit structure may include a central magnetic part and a side magnetic part, wherein the central magnetic part and the side magnetic part are spaced apart to form a magnetic gap 202. The sound-generating device 200 also includes a diaphragm assembly 203 and a voice coil 204. One end of the voice coil 204 is connected to the diaphragm assembly 203, and the other end of the voice coil 204 is inserted into the magnetic gap 202, so that when energized, it is driven by the magnetic field to vibrate and generate sound. The central magnetic part includes a central magnet 205a and a central magnetic guide plate 101a, and the side magnetic part includes a side magnet 205b and a side magnetic guide plate 101b. The central magnet 205a and the side magnet 205b together form a magnet assembly to provide magnetic flux to the magnetic circuit. One end of the central magnet 205a is connected to the magnetic yoke 101c, and the other end is connected to the central magnetic plate 101a; one end of the side magnet 205b is connected to the magnetic yoke 101c, and the other end is connected to the side magnetic plate 101b. With this arrangement, the magnetic flux forms a closed loop via the magnetic yoke 101c, the central magnet 205a, the central magnetic plate 101a, the magnetic gap 202, the side magnetic plate 101b, and the side magnet 205b, resulting in a high-intensity magnetic field within the magnetic gap 202, thereby enhancing the driving force of the voice coil 204 and the sensitivity of the sound-generating device 200.

[0100] Optionally, the magnet assembly includes a center magnet 205a and a side magnet 205b.

[0101] Optionally, refer to Figure 2 The surfaces of the central magnetic plate 101a, the side magnetic plates 101b, and the magnetic yoke 101c are provided with the first coating as described above. Figure 2 (not shown in the image), second coating 102b and third coating ( Figure 2 (not shown in the image) to achieve synergistic optimization of magnetic conductivity, corrosion resistance and adhesion.

[0102] Compared with conventional technology, the beneficial effects of the sound-generating device provided in the embodiments of the present invention are the same as those of the magnetic plate assembly provided in the above embodiments, and other technical features in the sound-generating device are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0103] This invention also provides an electronic device, including the magnetic plate assembly or sound-generating device described above.

[0104] In this embodiment, electronic devices include mobile phones, laptops, tablets, VR (Virtual Reality) devices, AR (Augmented Reality) devices, TWS (True Wireless Stereo) earphones, smart speakers, smart wearable devices, etc.

[0105] Compared with conventional technology, the beneficial effects of the electronic device provided in the embodiments of the present invention are the same as those of the magnetic conductive plate assembly provided in the above embodiments, and other technical features of the electronic device are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0106] To ensure that the details and operations of the above embodiments of the present invention can be clearly understood by those skilled in the art, and to demonstrate the significant advancements in the performance of the embodiments of the present invention, the following examples illustrate the above technical solutions. It should be noted that the following descriptions are merely exemplary and not intended to limit the specific scope of the present invention.

[0107] Example 1 A body portion is provided, with SPCC as the substrate and a pre-plating weight of 0.5 g. The body portion is subjected to alkaline washing to remove oil, acid washing to remove rust, and activation treatment before electroplating to form a 3 μm nickel-cobalt alloy coating on each surface of the body portion. The bottom surface of the body portion (i.e., the position corresponding to the third coating) is masked with tape and further electroplated to form a 4 μm nickel-cobalt alloy coating on the peripheral and top surfaces of the body portion. The top surface of the body portion (i.e., the position corresponding to the second coating) and the bottom surface of the body portion (i.e., the position corresponding to the third coating) are masked with tape and further electroplated to form a 5 μm nickel-cobalt alloy coating on the peripheral surface of the body portion. The second coating is sealed with an epoxy resin sealing agent, and the third coating is primed with a silane coupling agent to obtain a magnetic plate. The magnetic conductive plate has an average thickness of 15 μm for the first coating, 7 μm for the second coating, and 3 μm for the third coating. The cobalt content of the nickel-cobalt alloy coating is 20%. The plating solution includes: 300 g / L nickel sulfate, 50 g / L cobalt sulfate, 35 g / L boric acid, 30 g / L nickel chloride, and a pH buffer. The electroplating conditions are: pH 3-4, temperature 40-50℃, and current density 5-7 A / dm³. 2 .

[0108] Example 2 A body portion is provided, with SPCC substrate and a pre-plating weight of 0.5 g. After alkaline washing to remove oil, acid washing to remove rust, and activation treatment, the bottom surface of the body portion (i.e., the position corresponding to the third plating layer) is masked with tape and electroplated to form a 7 μm nickel-cobalt alloy plating layer on the surface of the body portion. The top surface (i.e., the position corresponding to the second plating layer) and the bottom surface (i.e., the position corresponding to the third plating layer) of the body portion are masked with tape and further electroplated to form a 5 μm nickel-cobalt alloy plating layer on the peripheral side surface of the body portion. The second plating layer is sealed with epoxy resin sealing agent to obtain a magnetic plate. The magnetic conductive plate has an average thickness of 15 μm for the first coating and 7 μm for the second coating. The cobalt content of the nickel-cobalt alloy coating is 20%. The plating solution includes: 300 g / L nickel sulfate, 50 g / L cobalt sulfate, 35 g / L boric acid, 30 g / L nickel chloride, and a pH buffer. The electroplating conditions are: pH 3-4, temperature 40-50℃, and current density 5-7 A / dm³. 2 .

[0109] Comparative Example 1 The product consists of a body portion made of SPCC (Silicone Carbon), weighing 0.5 g before plating. The body portion undergoes alkaline washing to remove oil, acid washing to remove rust, and activation treatment before electroplating to form a 6 μm pure nickel plating layer on its surface, resulting in a magnetic plate. The average thickness of the pure nickel plating layer on the magnetic plate is 6 μm. The plating solution includes: 300 g / L nickel sulfate, 35 g / L boric acid, 30 g / L nickel chloride, and a pH buffer. Electroplating conditions are: pH 3-4, temperature 40-50℃, and current density 5-7 A / dm³. 2 .

[0110] The physical properties of the magnetic plates in Examples 1-2 and Comparative Example 1 were tested, and the results are shown in Table 1 below: Table 1

[0111] In Table 1, the test positions for charge transfer resistance in Examples 1-2 are the corresponding positions of the second coating layer, and the same positions are tested in Comparative Example 1; the test positions for surface tension in Example 1 are the corresponding positions of the third coating layer, and the same positions are tested in Comparative Example 1 and Example 2; the saturation magnetic induction intensity is tested using a VSM (vibrating sample magnetometer) after the coating is peeled off; the test positions for elastic modulus are the corresponding positions of the second coating layer in Examples 1-2, and the same positions are tested in Comparative Example 1, and the test is performed using a nanoindentation tester.

[0112] Based on the experimental results above, it can be seen that the second coatings in Examples 1 and 2 are thicker than those in Comparative Example 1, and cobalt atoms are also added. The addition of cobalt atoms refines the matrix grain size of the coating to a certain extent, resulting in improved corrosion resistance and elastic modulus compared to the pure nickel coating in Comparative Example 1. Furthermore, the surface of the third coating in Example 1 is treated with a primer, resulting in higher surface energy and better adhesion, thus leading to greater surface tension. In Example 2, the position corresponding to the third coating in Example 1 is the body portion. After cleaning, although the surface energy does not reach the level of primer treatment, it is significantly higher than that of the pure nickel coating (i.e., Comparative Example 1). Furthermore, since the atomic magnetic moment of cobalt atoms is 1.72 μB and that of nickel atoms is 0.6 μB, the addition of cobalt atoms can greatly increase the magnetic moment content in the coating. Combined with the interaction between the two, the coatings in Examples 1 and 2 have a higher saturation magnetic induction intensity compared to Comparative Example 1.

[0113] Furthermore, the magnetic plates of Example 1 and Comparative Example 1 were assembled in a magnetic circuit structure and combined with the same diaphragm assembly to form a loudspeaker. Their acoustic performance was tested, and the results are as follows: Figure 3 As shown. According to Figure 3 It can be seen that, in the 1K-10Khz range, Example 1 has an average sensitivity that is 0.33 dB higher than that of Comparative Example 1, which means it has higher sensitivity. The higher the sensitivity, the faster the response to sound and the higher the loudness.

[0114] In summary, the magnetic plate assembly provided by the embodiments of the present invention not only ensures excellent magnetic permeability and corrosion resistance, but also has good structural integrity.

[0115] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the patent protection scope of the present invention.

Claims

1. A magnetic conductive plate assembly, characterized in that, The magnetic plate assembly includes: a body portion, a first coating layer on the peripheral side of the body portion, and a second coating layer on the top surface of the body portion. Both the first coating layer and the second coating layer are soft magnetic metal coating layers composed of polycrystalline materials. The average thickness of the first coating layer is 1.2 to 5 times the average thickness of the second coating layer.

2. The magnetic conductive plate assembly as described in claim 1, characterized in that, The average thickness of the first coating is 3~50 μm; And / or, the average thickness of the second coating is 1~20 μm; And / or, the average thickness of the first coating is less than or equal to 50% of the average thickness of the body portion.

3. The magnetic conductive plate assembly as described in claim 1, characterized in that, The bottom surface of the main body is provided with a third coating, which is a soft magnetic alloy coating composed of polycrystalline materials, and the average thickness of the third coating is 0.05 to 1 times the average thickness of the second coating.

4. The magnetic conductive plate assembly as described in claim 3, characterized in that, The average thickness of the third coating is 1~10 μm; And / or, the surface tension of the third coating is 20~70 dyn / cm; And / or, the roughness of the third coating is 0.05~3 μm; And / or, the third coating contains at least two elements selected from iron, cobalt, and nickel; And / or, the saturation magnetic induction intensity of the third coating is 0.5~3 T; And / or, the third coating is primed, and the primed agent used in the primed treatment includes at least one of silane coupling agent, epoxy primer and acrylic primer; And / or, the third coating is prepared by at least one of electroplating, electroless plating, diffusion plating and physical vapor deposition; And / or, the third coating is a single-layer or multi-layer structure.

5. The magnetic conductive plate assembly as claimed in claim 1, characterized in that, The second coating undergoes a sealing treatment, wherein the sealing agent used in the sealing treatment includes at least one of water-based sealing agents, oil-based sealing agents, and nano-composite sealing agents; And / or, the charge transfer resistance of the second coating in a 3.5 wt.% NaCl solution is 1~200 KΩ·cm. 2 .

6. The magnetic plate assembly as claimed in claim 1, characterized in that, The first coating contains at least two elements selected from iron, cobalt, and nickel; And / or, the second coating contains nickel, and the mass percentage of nickel in the second coating is greater than 60%.

7. The magnetic plate assembly as claimed in claim 6, characterized in that, The saturation magnetic induction intensity of the first coating is 0.5~3 T; And / or, the elastic modulus of the first coating is 100~300 GPa; And / or, the elastic modulus of the second coating is 100~300 GPa.

8. The magnetic plate assembly as claimed in claim 1, characterized in that, The first coating is prepared by at least one of electroplating, electroless plating, diffusion plating and physical vapor deposition; And / or, the second coating is prepared by at least one of electroplating, electroless plating, diffusion plating and physical vapor deposition; And / or, the first coating is a single-layer or multi-layer structure; And / or, the second coating is a single-layer or multi-layer structure.

9. A sound-generating device, characterized in that, The sound-generating device includes a housing and a magnetic circuit structure disposed on the housing. The magnetic circuit structure includes a magnet assembly and a magnetic guide plate assembly as described in any one of claims 1 to 8. The magnetic guide plate assembly includes at least one of a magnetic guide yoke and a magnetic guide plate disposed at one end of the magnet assembly away from the magnetic guide yoke.

10. An electronic device, characterized in that, The electronic device includes a magnetic plate assembly as described in any one of claims 1 to 8, or a sound-generating device as described in claim 9.

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